Well, the advice at the time was that it is a better way to go... so XP sits in it's own partition, my XP "backup" installation sits in a second (allows me to boot the PC if the main XP dies - hey I used to use ME), all my stored files sit in a third, the fourth has all my programs, and the fifth used to be a Linux installation.
There are advantages, for example I can format just one partition instead of formatting the whole disk and losing everything.
My second drive, a 120Gb, will only have a couple of partitions as it will be used mainly for storing video projects.
As I said, all the techie forums seemed to agree that multiple partitions are the way to go, but I don't have a sound technical reason!